1. Field of the Invention
This invention relates to the calibration and testing of infrared radiation detection devices.
2. Description of the Prior Art
Infrared detection devices such as infrared receivers, forward looking infrared systems, infrared imaging systems and imaging radiometers and are designed to detect differences in heat radiated from an object or scene. There is a need to calibrate and measure the performance of such devices, that is, to provide a measure of how well the device can resolve the image of an object of a given temperature in a background having a temperature near that of the object itself. A high resolution detection device must have the capability of perceiving small differences in temperature among closely spaced objects in the field of view.
Apparatus and methods for calibrating and testing infrared detectors are well-known; see, e.g., U.S. Pat. Nos. 3,596,096; 3,845,295; 3,971,886; 3,986,384; and 4,047,032. However, the disclosed apparatus and methods suffer from one or more of the following disadvantages: they do not provide a desired spatial resolution of temperature differentials (.DELTA.T) of about 0.01.degree. C., or are cumbersome, or are not suitable for use in a remote field environment having uncontrolled ambient temperature or are expensive.